Manual insertion of a catheter into a patient is relatively standard surgery. However, as this procedure is performed with X-ray monitoring, the surgeon in charge of the procedure is exposed to substantial radiation when performing such operations on numerous patients.
To reduce the risk to the surgeon, such insertions can be automated using robots. Such automation is complex, because the act of holding the catheter is complex. The catheter is bathed in preservative liquid and must remain sterile. In addition, it should be possible to alternate between rotational and translational movements of the catheter. And of course these robotic systems must be completely reliable.
Recently, a drive system was proposed in U.S. Pat. No. 7,927,310 that manages both the translational and rotational movements of the catheter. The catheter is retained on a plate that rotates relative to a base in order to provide the rotation. The plate itself comprises a mechanism to provide the translation. In addition, there are external motors fixed to the frame, and systems for transferring motion to the catheter. It is preferred not to have embedded motors for reasons concerning power capacity, footprint, and sterility.
However, the problem remains of emergency removal of the catheter from the mechanism. We want to be able to uncouple the catheter from the mechanism as easily as possible when there is an emergency, allowing the surgeon to resume the operation manually. In the above document, because the catheter traverses closed passages, such uncoupling is not allowed for. In addition, the possibility for uncoupling must not adversely affect the normal operation of the robot. In other words, it must not reduce the maneuverability or reliability of the robot.
Also known is WO2005/117,596. This document presents two embodiments. The second embodiment requires embedded motors which, as explained above, is not desirable. The first embodiment provides slotted gear wheels that are independent of each other for the translation and rotation, requiring calculation of the nearest position where the two slots can be aligned, which is complex and dangerous.
The present invention is intended to overcome these disadvantages.